Other Causes of Twitch-Like Symptoms Twitching is not the only sign of abnormal firing of neurons. Spasticity and clonus can easily be perceived as twitching, but medically, they're different.

In legs, test rapidity and range of foot tapping (slowed in Parkinson's disease and spasticity) and for clonus (brisk passive extensions of ankle). A sensitive test for spasticity is the Trömner ...